Seat Assembly Having Sinuous Springs

ABSTRACT

A seat assembly for insertion into a piece of furniture has a frame having opposed sides. Each side may have openings therein for supporting clips. Upper and lower sinuous wires extend generally across the frame. Upper stabilizer wires are secured to the upper sinuous wires and maintain the spacing thereof. The clips secure each of the sinuous wires to the frame. Coil springs are secured to the upper stabilizer wires and the lower sinuous wires. The clips securing the upper and lower sinuous wires alternate along the sides of the frame.

FIELD OF THE INVENTION

The present invention relates to a seat assembly for use in furniture.

BACKGROUND OF THE INVENTION

Prior to the use of springs, seat cushions were simply stuffed withmatting, fill or other soft fibers. After a period of use, the cushionstuffing would settle, often resulting in a hard, lumpy, uncomfortablecushion.

The advent of the coil spring solved many of the prior problems. Theearly coil springs were placed in a frame under the seat cushion paddingin a sufficient number of rows to provide proper seating support. Thecoil springs advantageously provided consistent spring resiliencethroughout the seating area. However, this manner of providing cushionseating was expensive due to the large number of coil springs needed tosupport a cushion in a consistent manner.

The development of the sinuous spring caused many manufacturers to adoptthis spring as an economical substitute for the prohibitively pricedcoil spring structure. The sinuous springs have a zigzag pattern and aregenerally disposed in an upwardly bending arc between two parallel sidesof a frame. Rows of sinuous wire springs are generally attached in aparallel alignment between the front and rear walls of cushion seatingframes, offering both comfort and resilience. While the substitution ofsinuous springs for coil springs reduced the amount of wire and the costof the springs by between 60 and 80 percent, the firmness and comfortoffered by only the rows of sinuous wires did not meet all of the needsof manufacturers. Heavier people found that the sinuous wire springsdesigned for people of average weight do not provide the desiredresilience and have a tendency to bottom out. “Bottoming out” as used inthis document, is a term of art generally referring to that condition inwhich the force which has been applied to the springs in a cushionexceeds the ability of the springs to resiliently resist the appliedforce, thus causing the springs to sag to a position in which furthertravel of the springs is restrained by supporting structure or by thefully extended springs. The use of stronger, stiffer springs, whileproviding more comfort to heavier persons, proved to be too hard anduncomfortable for lighter persons. The problem of providing propersupport and resilience in cushion seating for heavier persons has alsobeen compounded by the fact that the average person of today is biggerand heavier than the average person of 40 years ago. In addition,today's consumer is more sophisticated and demanding than in the past.Thus, the requirements for seat cushion constructions which can provideacceptable levels of support and comfort to a broader spectrum of peopleare more demanding today than in the past.

Attempts to overcome the aforementioned problems and to provide cushionseating with comfort and resilience have included the combination ofsinuous springs and coil springs. The coil springs were often placedbetween a flexible base support and the sinuous springs to provide moreresilience to the sinuous spring. For example, U.S. Pat. No. 6,170,915,which is fully incorporated by reference herein, discloses a seatassembly incorporating both coil springs and sinuous springs. The coilsprings of such a spring assembly extended between upper sinuous springsand lower support wires.

Later, a seat cushion incorporating both coil springs and sinuoussprings was developed which replaced lower support wires with lowersinuous wires to support the coil springs. Such a seat cushion is shownin FIGS. 1 and 2 of this document. As described below, the weak point insuch a seat cushion is the location of the clips securing the coilsprings to the lower sinuous wires since the load is ultimately borne bythe bottom layer. Another drawback to the prior art seat cushion shownin FIGS. 1 and 2 is that twice as many lower sinuous wires andadditional clips must be used compared to the seat assembly of thepresent invention. The prior art seat assembly components are moredifficult to assemble than the components of the present invention. Thepresent invention improves the durability and performance of the seatassembly by replacing the two short pieces of bottom sinuous wires withone longer piece of sinuous wire, which spans from one side of the frameto an opposed side of the frame. The coil springs rest on top of thelonger continuous sinuous wires, as opposed to being suspended betweentwo shorter pieces of sinuous wires. The seat assembly of the presentinvention has no load transmitted through three-prong clips, and iseasier to assemble because the lower sinuous wires may be secured toopposed sides of the frame before the coil springs are secured to thelonger lower sinuous wires.

SUMMARY OF THE INVENTION

The present invention provides an improved seat assembly comprising aframe having four sides for supporting the assembly. The frame may bemade of metal or wood or any other desirable material, includingplastic. The seat assembly further comprises a plurality of clipsattached to each side of opposed sides of the frame. A portion of eachof the clips may be located in one of the openings in one of the sidesof a metal frame.

The seat assembly further comprises a plurality of generally parallelupper sinuous wires. Each of the upper sinuous wires extends betweenopposed sides of the frame. In one embodiment, the upper sinuous wiresextend generally parallel the sides of the frame. End portions of eachof the upper sinuous wires are secured in opposed clips. Upperstabilizer wires extend transversely to the upper sinuous wires and aresecured to the upper sinuous wires. In order to reduce noise due tometal-on-metal, each of the stabilizer wires may be coated in paper orplastic. In one embodiment, each of the stabilizer wires is secured tomultiple upper sinuous wires with three-prong clips.

The seat assembly further comprises a plurality of generally parallellower sinuous wires extending between opposed sides of the frame. In oneembodiment, the lower sinuous wires extend generally parallel the sidesof the frame and parallel the upper sinuous wires. End portions of eachof the lower sinuous wires are secured in opposed clips. In oneembodiment, each of the lower sinuous wires is bowed or arced in adownward direction, while each of the upper sinuous wires is bowed orarced in an upward direction.

The seat assembly further comprises a plurality of coil springs. Eachcoil spring has an upper end turn, a lower end turn and a plurality ofcentral convolutions between the end turns. In one embodiment, the upperend turn of each coil spring is a knotted end turn, and the lower endturn of the coil spring is an unknotted end turn. In this embodiment,the diameter of the upper end turn of each coil spring is larger thanthe lower end turn of the spring. The upper end turn of each coil springis secured to the upper stabilizer wires. The lower end turn of eachcoil spring is secured to one of the lower sinuous wires. The clipssecuring the upper and lower sinuous wires to opposed sides of the framealternate along the front and rear of the frame.

The present invention provides an improved seat assembly which is easierto assemble than the previous version of the seat assembly. The improvedseat assembly increases the structural integrity of the product. Theimproved seat assembly may be used with steel frames usable in motionfurniture.

These and other objects and advantages of the present invention shall bemade apparent from the accompanying drawings and the descriptionthereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention and,together with the general description of the invention given above andthe detailed description of the embodiments given below, serve toexplain the principles of the present invention.

FIG. 1 is a perspective view of a prior art seating product.

FIG. 1A is a perspective view of a portion of the prior art seatingproduct of FIG. 1.

FIG. 2 is a perspective view of a seating product constructed inaccordance with the present invention showing the environment of theseating product.

FIG. 3 is a perspective view of the seating product of FIG. 2.

FIG. 4 is a perspective view of a portion of the seating product of FIG.3.

FIG. 5 is a cross-sectional view taken along the line 5-5 of FIG. 3.

FIG. 6 is a perspective view of another embodiment of seating productconstructed in accordance with the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference to FIGS. 1 and 1A, there is shown a prior art seatassembly 10. The prior art seat assembly includes a rectangular frame12, two coil springs 14, upper sinuous springs 16 secured to the frame12 with clips 18, and lower sinuous springs 20. As best shown in FIG.1A, each coil spring 14 is suspended by two lower sinuous springs 20. Asbest shown in FIG. 1A, each lower sinuous spring 20 is secured to theframe with a clip 22 at one end and with a different three-prong clip 24at the other end. When a heavy load is placed on the seat assembly shownin FIGS. 1 and 1A, the load transfers through the coil springs to thebottom of the coil springs, through the three-prong clips to the lowersinuous wires and, ultimately to the rectangular frame. Since the seatload is ultimately borne by the bottom layer of sinuous springs, theweak point in the system is the three-prong clips 24.

FIG. 2 illustrates the seat assembly 26 of the present invention as usedin a recliner 28 shown in phantom. Although the seat assembly 26 isillustrated being used in a recliner, the seat assembly 26 of thepresent invention may be used in any location in any piece of furniture.

The seat assembly 26 comprises a generally rectangular metal frame 30having four sides: a front 32, a rear 34 and two opposed sides 36. Inthe illustrated embodiment, the frame 30 comprises two pieces; agenerally U-shaped piece 38 and a linear rear piece 40 welded together.The generally U-shaped piece 38 comprises the front 32 and two opposedsides 36 of the metal frame 30. The linear rear piece 40 comprises therear 34 of the metal frame 30. The metal frame 30 has a plurality ofindentations 31 with openings 33 at different locations to assist insecuring the frame 30 to different pieces of furniture. The illustratedindentations 31 and openings 33 are not intended to be limiting.

As shown in FIG. 5, the generally U-shaped piece 38 has a generallyrectangular cross-section comprising a top wall 42, a bottom wall 44, aninner wall 46, and an outer wall 48 defining a hollow interior 50. Asshown in FIG. 5, the linear rear piece 40 is generally L-shaped incross-section, having a top wall 52 and a side wall 54 extendingdownwardly from an outer edge of the top wall 52.

As best shown in FIGS. 3-5, the side wall 54 of the linear rear piece 40of frame 30 has a plurality of spaced openings 56 in the form of holes.As shown in FIG. 5, the outer wall 48 of the front 32 of the generallyU-shaped piece 38 of frame 30 has a plurality of spaced openings 58 inthe form of holes. The openings 56, 58 are spaced identically along thewidth of the front and rear 32, 34 of the frame 30 for purposesdescribed below. In identical locations along the width of front andrear 32, 34 of the frame 30, clips 60 are secured inside the openings58, 56, respectively. As shown in FIG. 5, a portion 62 of each clip 60located along the front 32 of frame 30 resides inside the hollowinterior 50 of the generally U-shaped piece 38. Similarly, a portion 62of each clip 60 located along the linear rear piece 40 of frame 30resides inside the side wall 54 of the linear rear piece 40. See FIG. 5.

As shown in FIGS. 2-5, the seat assembly 26 further comprises aplurality of generally parallel, upper sinuous wires 64. Each uppersinuous wire 64 has two opposed end portions 66, each end portion 66being secured inside a hook portion 68 of one of the metal clips 60. Theupper sinuous wires 64 are illustrated extending from front to back inthe seat assembly 26. However, the seat assembly may be such that theupper sinuous wires 64 extend from side-to-side. As best shown in FIG.5, each upper sinuous wire 64 is upwardly bowed to provide resilientsupport to loads placed on the seat assembly 26.

The seat assembly 26 further comprises a plurality of upper stabilizerwires 70. Each of the two upper stabilizer wires 70 shown in theembodiment illustrated extends transversely to the upper sinuous springs64 and is fastened to each of the upper sinuous springs 64 with afastener 72 in the form of a clip. Each of the upper stabilizer wires 70is not connected to the frame 30 and extends less than the full width ofthe seat assembly 26. Each of the upper stabilizer wires 70 ispreferably covered in paper or plastic to prevent squeaking or noise,i.e., metal-on-metal contact.

As shown in FIGS. 2-5, seat assembly 26 further comprises a plurality ofgenerally parallel lower sinuous wires 74. Each lower sinuous wire 74has two opposed end portions 76, each end portion 76 being securedinside a hook portion 68 of one of the metal clips 60. The lower sinuouswires 74 are illustrated extending from front to back in the seatassembly 26. However, the seat assembly may be such that the lowersinuous wires 74 extend from side-to-side. As best shown in FIG. 5, eachlower sinuous wire 74 is downwardly bowed to provide resilient supportto loads placed on the seat assembly 26 transferred through the coilsprings 80. Unlike the prior art, each lower sinuous wire 74 extends thefull length of the seat assembly 26 from the front 32 to the rear 34 ofthe frame 30, which reduces the number of potential weak points in theseat assembly. When a heavy load is placed on the seat assembly 26, theload transfers through the coil springs 80 to the bottom of the coilsprings 80, to the lower sinuous wires 74 and, ultimately to therectangular frame 30. Since the seat load is ultimately borne by thebottom layer of sinuous springs 74 which support the coil springs 80,the weak point in the system, the three-prong clips in the prior art hasbeen eliminated, resulting in a stronger, more durable seat assembly.

As shown in FIG. 3, a plurality of coil springs 80 (two in theembodiment shown) are secured to the upper stabilizer wires 70 withfasteners 82, each fastener 82 being in the form of a three-prong clip.Each coil spring 80 is also secured to one of the lower sinuous wires 74with two fasteners 84, each fastener 84 being in the form of athree-prong clip. Each coil spring 80 is made of one piece of wire andhas an upper end turn 86, a lower end turn 88, and a plurality ofcentral convolutions 90 between the end turns. In the embodimentillustrated, the upper end turn 86 is a knotted end turn, and the lowerend turn is an unknotted end turn. In this embodiment, the diameter ofthe upper end turn 86 is greater than the diameter of the lower end turn88. Although not shown, either of the end turns may be knotted orunknotted. The end turns may be any desired diameter, including the samediameter. Although the central convolutions 90 are illustrateddecreasing in diameter from top to bottom, they may be any desired sizeor configuration, such as in an hourglass-shaped coil spring.

FIG. 6 illustrates another embodiment of seat assembly 92. The onlydifference between seat assembly 92 and seat assembly 26 is the frame.Instead of the metal frame 30 of seat assembly 26, seat assembly 92 hasa generally rectangular wooden frame 94. The clips 60 may be secured tothe wooden frame 94 in any known manner. The frame 94 has a front 96, arear 98 and two opposed sides 100.

While the present invention has been illustrated by the description ofembodiments thereof, and while the embodiments have been described inconsiderable detail, it is not intended to restrict or in any way limitthe scope of the appended claims to such detail. Additional advantagesand modifications will readily appear to those skilled in the art. Forexample, the coil springs may have a uniform diameter.

The invention in its broader aspects is, therefore, not limited to thespecific details, representative apparatus and method, and illustrativeexamples shown and described. Accordingly, departures may be made fromsuch details without departing from the spirit or scope of the generalinventive concept.

Having described the invention, what is claimed is:
 1. A seat assemblycomprising: a frame having four sides; a plurality of clips attached toeach side of opposed sides of the frame; a plurality of generallyparallel upper sinuous wires, each of the upper sinuous wires extendingbetween the opposed sides of the frame, end portions of each of theupper sinuous wires being secured in opposed clips; a plurality of upperstabilizer wires extending transversely to and fastened to the uppersinuous wires; a plurality of generally parallel lower sinuous wires,each of the lower sinuous wires extending between the opposed sides ofthe frame, end portions of each of the lower sinuous wires being securedin opposed clips; a plurality of coil springs, each coil spring havingan upper end turn, a lower end turn and a plurality of centralconvolutions between the end turns, the upper end turn of each coilspring being secured to the upper stabilizer wires and the lower endturn of each coil spring being secured to one of the lower sinuouswires, wherein the clips securing the upper and lower sinuous wires tothe opposed sides of the frame alternate along the opposed sides of theframe.
 2. The seat assembly of claim 1 wherein each of the stabilizerwires is coated to prevent wire-on-wire noise.
 3. The seat assembly ofclaim 1 wherein each of the coil springs has upper and lower end turnsof different diameters.
 4. The seat assembly of claim 1 wherein each ofthe coil springs has a knotted upper end turn.
 5. The seat assembly ofclaim 1 wherein each of the coil springs has an unknotted lower endturn.
 6. The seat assembly of claim 1 wherein only the lower end turn ofeach of the coil springs is secured to one of the lower sinuous wires.7. A seat assembly comprising: a frame having four sides; a plurality ofclips attached to opposed sides of the frame; a plurality of generallyparallel upper sinuous wires, each of the upper sinuous wires extendingbetween the opposed sides of the frame, end portions of each of theupper sinuous wires being secured in opposed clips; a plurality of upperstabilizer wires extending transversely to and fastened to the uppersinuous wires; a plurality of generally parallel lower sinuous wires,each of the lower sinuous wires extending between the opposed sides ofthe frame, end portions of each of the lower sinuous wires being securedin opposed clips; a plurality of coil springs, each coil spring havingan upper end turn, a lower end turn and a plurality of centralconvolutions between the end turns, the upper end turn of each coilspring being secured to the upper stabilizer wires and the lower endturn of each coil spring being secured to one of the lower sinuouswires, wherein only the lower end turn of each of the coil springs issecured to the sinuous wires.
 8. The seat assembly of claim 7 whereineach of the stabilizer wires are coated to prevent wire-on-wire noise.9. The seat assembly of claim 7 wherein each of the coil springs hasupper and lower end turns of different diameters.
 10. The seat assemblyof claim 7 wherein each of the coil springs has a knotted upper endturn.
 11. The seat assembly of claim 7 wherein each of the coil springshas an unknotted lower end turn.
 12. The seat assembly of claim 7wherein the clips securing the upper sinuous wires and the clipssecuring the lower sinuous wires alternate along the opposed sides ofthe frame.
 13. A seat assembly comprising: a frame; a plurality of clipssecured to each side of opposed sides of the frame; a plurality ofgenerally parallel upper and lower sinuous wires, each of the upper andlower sinuous wires extending between two of the clips; a plurality ofupper stabilizer wires secured to the upper sinuous wires; a pluralityof coil springs, each coil spring having an upper end turn, a lower endturn and a plurality of central convolutions between the end turns, theupper end turn of each coil spring being secured to the upper stabilizerwires and the lower end turn of each coil spring being secured to one ofthe lower sinuous wires, wherein the upper and lower sinuous wiresalternate longitudinally along the opposed sides of the frame.
 14. Theseat assembly of claim 13 wherein each of the stabilizer wires arecoated to prevent wire-on-wire noise.
 15. The seat assembly of claim 13wherein each of the coil springs has upper and lower end turns ofdifferent diameters.
 16. The seat assembly of claim 13 wherein each ofthe coil springs has a knotted upper end turn.
 17. The seat assembly ofclaim 13 wherein each of the coil springs has an unknotted lower endturn.
 18. The seat assembly of claim 13 wherein only the lower end turnof each of the coil springs is secured to the sinuous wires.